Nipples, like breasts, come in all shapes and sizes, and women in the UK are now seeking uniformity, hence the growing beauty trend of 'tittooing'.

Semi-permanent tattoos to darken and define nipples are becoming "the fashion" according to a report in The Telegraph. The two hour process costs around NZD$2,170 (per set), and the tattoos need to be touched-up every year to avoid fading.

The 'tittooing' process originated as a procedure for women who had undergone breast reconstruction, but is now serving women who want to look like the - often digitally altered - girls of page three and beyond.

The most common request is to darken the nipple and surrounding areola area, but some women also get 'tittooed' to achieve symmetry.

There are at least 15 independent 'tittoo' experts in the Liverpool region according to The Telegraph, with clinician Gail Proudman telling them she sees more than three women a week.

"A lot of people want their nipples made darker. It's the fashion. Some people think theirs are too pink or their boyfriends want them done. I think sometimes they are doing it because they are conscious of them being pale and they think it's fashionable to have dark nipples."